The present invention relates generally to an improved electronic image printer and, more particularly, to apparatus for controlling the operation thereof, especially the presentation of data to image recording material.
Various forms of electronic imaging printers of the type which generate and record images representative of electronic information on image recording material are well known in the art.
One known kind of printer is described in U.S. Pat. No. 4,179,183, wherein there is disclosed a focused laser beam scanning apparatus for use in printing images. Included is a polygonal mirror which is used for achieving a fast scan motion of the laser beam across image recording material. With light scanning printer systems of this type, completion and repeatability of successive scanning lines is important. This is extremely so when the resultant image is to be of photographic quality. It should be understood that misplacement of even one scanning line can affect adversely the quality of the image produced.
This invention is related to the type of electronic image printer described in the above-noted application. Essentially, the application discloses a printer having a system under open loop control which is responsible for simultaneously generating fast and slow scanning movements needed for image production as well as energizing light emitting diodes responsive to rotation of a rotary motor driving the scanning movements. In such a printer, it is important to properly present the data to the light emitting elements at the appropriate time. In this regard, pixel time and placement variations should remain within constraints which provide acceptable photographic type images from one scan line to the next. In this manner, the pixels are placed at preselected positions so that the resultant image lines are straight and do not overlap. Clearly, while electronic printers of the type described in the aforementioned application show desirable performance there is ongoing interest in improving the operational aspects of such printers.